You’d think he’d remember his name. After all, Ronny Jackson is the former White House physician who likely lied about Donald Trump’s weight and health, then became one of the former president’s staunchest supporters as a Texas Congressman. But a funny thing happened on Saturday night as Trump demanded that President Joe Biden take a cognitive test: The guy who could remember “Person, woman, man, camera, TV” couldn’t remember the name of his former physician. Awkward. “I think [Biden] should take a cognitive test like I did,” Trump said during a speech at a convention of Turning Point Action i…